In the telephone number space of the public telephone network, essentially irrespective of whether the telephone network takes the form of a fixed network or a mobile network, the number of service facilities selectable by dialing a service telephone number appears to be rising steadily. Via such selectable service devices, for example, it may be possible to retrieve announcement and/or information services via the telecommunications network or also to enable audio and/or video conferences. Normally the service telephone numbers associated with the respective service devices for selecting particular services are subsumed in special telephone number ranges.
In this respect there are destination telephone numbers for which the connection charges are significantly higher than the normal rate. In Germany, for example, destination telephone numbers having higher connection charges may be found, for instance, in the telephone number ranges 00xx, 0137xx, 015xx, 016xx, 017xx etc. There also, for example, are destination telephone numbers having rates that can be freely determined by the respective provider. Such destination telephone numbers exist, for example, in the telephone number ranges 11xx, 012xx, 019xx, the service telephone numbers in the number range 0190x and the future number range 0900x being used in Germany, for example.
Telephone numbers having higher rates and/or for which the rates can be freely set may be used by companies for marketing the most varied contents and/or services that go beyond the basic use of the telecommunications network. Examples of services offered for a fee, that is, so-called added-value services, include, among others, information services, ordering hotlines, special consultations and/or weather information by telephone.
For example, in Germany, the telephone numbers from the 0190x range are currently allotted to the network operators of the respective telephone network in blocks of 1000, the telephone numbers 090-1 through 0190-9 being based on fixed rate structures in this case. For telephone numbers from the subrange 0190-0, no rate limits are currently prescribed, for example, in order to allow interested providers of fee-based services to set their own rates appropriate to the respective added-value service. This meets the market's requirements for flexible, performance-related rates, while providing users of such services with an anonymous, convenient method of payment by telephone bill without having to divulge bank data or a credit card number. Normally, the user of such a service pays by his call, that is, the collection occurs via the telephone bill, and the call for an added-value service use in this case would be charged at a higher fee than a regular telephone connection. In addition to legitimate providers making offers of value, however, dubious providers also use this form of marketing.
The telephone numbers of the dubious providers may be priced extremely high. Service offers from dubious providers often consciously exploit human weaknesses such as inattentiveness, credulity, and/or fear mongering. Further, the service users may be in part consciously or with fraudulent intent left in the dark regarding, for example, the amount of fees incurred with the use of the fee-based service. The number of subscribers who want to protect themselves against this growing threat is rising steadily. Frequently, however, the destinations or offers which are desirable or undesirable from the subscriber's perspective lie in close proximity in the telephone number space, are mixed and/or are subject to constant change such that the undesirable destinations are not known at all.
The current method of selecting providers, for example, of fee-based services, via specific telephone number ranges such as the (0)190 telephone number range, does not sufficiently ensure that service users are comprehensively informed about the type, content, and fees incurred following the selection of the respective service device and that the service users availing themselves of the service thus offered always do so in a conscious manner. Consequently, in principle, this affects, albeit in different ways, all service users who make use of a fee-based service, for example, those by telephone, fax, SMS, MMS or PC.
Furthermore, dubious providers seek to generate calls to their service telephone number by all means. One available example of this is the so-called dialer, i.e., software which is able to establish connections at times without the knowledge on the part of an owner of a PC/computer. This can affect, for example, those Internet users who have not implemented appropriate protective measures such as the use of hardware/software-based dialer blockers, virus scanners or firewalls. Thus, for such users, the dialers may initially install themselves unbeknownst to the user and subsequently, following the installation of the software, for example, after the immediate disconnection of the current connection, may establish a telephone connection to a fee-based service telephone number automatically via the standard connection function in the remote data transmission network when the user dials into the Internet and/or directly when the operating system is launched.
Some defense options are available against undesired service use.
For example, when using the Internet, a hardware-based dialer blocker may be interconnected between the telephone jack and the modem. For this purpose, the dialer blocker is configured in such a way that a predefined number of telephone numbers can be programmed into it. A connection can be established exclusively via these telephone numbers. Any attempt to establish a connection via a telephone number that deviates from them is prevented.
Furthermore, software-based dialer warning programs such as “190-Warner” or “YAW” may be installed on a PC in order to monitor the remote data transmission network and/or the TAPI (Telephone Application Programming Interface) and CAPI (Cryptography Application Program Interface) interfaces. In this case, the user may specify which programs or via which telephone numbers an online connection may be established in an outgoing direction. All connection attempts beyond these restrictions are blocked and are deblocked or cleared only following an express authorization by the user.
Moreover, modern private branch exchanges may normally be programmed using a so-called black list. Depending on the technical design of the equipment, such a black list holds a certain number of freely programmable telephone numbers. In the event of a dialing attempt to the outside, that is, an outgoing telephone connection via a telephone number contained in the black list, the equipment blocks or rejects the connection set-up.
Further, net-based approaches on the part of the respective network operator may be available for blocking telephone number ranges for a certain subscriber terminal device. The protective mechanism here lies in the fact that upon request from a subscriber, the network operator ensures in his technical facilities such as, for example, the switching exchanges that from the respective subscriber terminal device it is not possible to select, for example, the 0190 telephone number range in the outgoing direction, that is, that this range is blocked. This permanent barrier also prevents any use of desired services within this telephone number range.
Security packages also may be available which allow incoming and outgoing connections on the user side to be admitted based on a white list or to be blocked on the basis of a black list. In detail, a variable connection barrier allows the user himself to block outgoing dial-up connections on his telephone, for example connections to 0190 telephone numbers, it being possible in each case to block only one of several predefined telephone number ranges.
Variable telephone number blocking, which is controlled via a telephone number list, allows the user to generate either white lists or black lists. Consequently, it is possible on the basis of a black list to block outgoing dial-up connections to undesired telephone numbers or telephone number groups as non-admissible destinations, while all other telephone numbers remain accessible. Alternatively, it is possible on the basis of a black list to clear only the outgoing dial-up connections to desired telephone numbers or telephone number groups as admissible destinations, while blocking all other telephone numbers. In this manner, the user is able to define up to 10 telephone numbers or telephone number groups, each having a maximum of 20 digits, and to program them by numeric code via the subscriber terminal device itself.
These available list spaces or the available capacities, however, are often insufficient for a differentiated filtering of telephone connections required from the perspective of the subscriber. In order to obtain sufficient security, entire telephone number ranges must be blocked as a consequence of this limited capacity. This has the consequence that the legitimate offers contained in these ranges are likewise no longer available.
All of the above-mentioned defense measures thus have one common disadvantage in that free access to service offers via a telecommunications network is made difficult or even impossible. In addition there is the fact that in some cases the task of taking possible protective measures may be too demanding for a layperson even if the person is prepared to bear the additional financial cost.